This invention pertains to the art of tapping conduits and more particularly to tapping a conduit such as a plastic gas line in order to establish communication with a service line. The invention is particularly applicable to tapping a main fluid line and will be described with particular reference thereto. However, it will be appreciated that the application has broader applications and may be advantageously employed in related environments and applications.
U.S. Pat. No. 4,809,735 to Volgstadt, et al. is commonly assigned to the same assignee as the present invention. It describes in detail a commercially successful tapping tee apparatus comprised of multiple parts. Particularly, a surrounding saddle or support assembly is received around the main conduit. A generally cylindrical body is integrally formed with the support assembly and receives a tapping assembly therein. An internally threaded passage extends through the body and is generally perpendicular to the longitudinal axis of the main line. The tapping assembly includes a cutter member that is selectively threadedly advanced through a sidewall of the main conduit, forming an opening as it is rotated through the sidewall. A spreading or tapered portion of the cutter member advances through the opening to firmly grip the inner wall of the main conduit when properly positioned in place. An elongated portion of the cutter member remains within the main conduit, generally radially inward of the tapered portion. An upper portion of the tapping assembly is subsequently threadedly retracted from the cutter member to establish fluid communication from the main line, through apertures provided in the cutter member, and to a branch or service line connected to the body.
A second embodiment also uses a two-part cutter but is modified so that material cut from the sidewall of the main conduit, or coupon as it is generally referred to, is removed from the interior of the main conduit. In most other respects, this modified embodiment works in much the same way to establish a fluid passage from the main conduit to a branch passage or service line.
Although commercially successful, there are areas where improvement is desired in the above described tapping assemblies. For example, the internally threaded passageway received in a tower portion of the body is relatively long to accommodate the above-described tapping assembly. Moreover, this arrangement still results in a relatively small bore that limits the amount of flow between the main conduit and the branch passage. Due to its complexity, the tapping assembly is rather expensive to manufacture. It also results in a relatively large profile or extended portion of the cutter member remaining in the main conduit. This is not particularly desired since it could potentially interfere with the passage of objects through the main conduit.
On the other hand, it is desirable to maintain a secure, easy to use arrangement that provides positive feedback to the installer or user of its proper installation. Likewise, it is desired to universalize the tools necessary to secure the assembly to the main.